Mercurial > hg > CbC > CbC_gcc
annotate gcc/predict.def @ 145:1830386684a0
gcc-9.2.0
| author | anatofuz |
|---|---|
| date | Thu, 13 Feb 2020 11:34:05 +0900 |
| parents | 84e7813d76e9 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* Definitions for the branch prediction routines in the GNU compiler. |
| 145 | 2 Copyright (C) 2001-2020 Free Software Foundation, Inc. |
| 0 | 3 |
| 4 This file is part of GCC. | |
| 5 | |
| 6 GCC is free software; you can redistribute it and/or modify it under | |
| 7 the terms of the GNU General Public License as published by the Free | |
| 8 Software Foundation; either version 3, or (at your option) any later | |
| 9 version. | |
| 10 | |
| 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 for more details. | |
| 15 | |
| 16 You should have received a copy of the GNU General Public License | |
| 17 along with GCC; see the file COPYING3. If not see | |
| 18 <http://www.gnu.org/licenses/>. */ | |
| 19 | |
| 20 /* Before including this file, you should define a macro: | |
| 21 | |
| 22 DEF_PREDICTOR (ENUM, NAME, HITRATE) | |
| 23 | |
| 24 This macro will be called once for each predictor. The ENUM will | |
| 131 | 25 be of type `enum br_predictor', and will enumerate all supported |
| 0 | 26 predictors. The order of DEF_PREDICTOR calls is important, as |
| 27 in the first match combining heuristics, the predictor appearing | |
| 28 first in this file will win. | |
| 29 | |
| 30 NAME is used in the debugging output to determine predictor type. | |
| 31 | |
| 32 HITRATE is the probability that edge predicted by predictor as taken | |
| 33 will be really taken (so it should be always above | |
| 34 REG_BR_PROB_BASE / 2). */ | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
35 |
| 0 | 36 |
| 37 /* A value used as final outcome of all heuristics. */ | |
| 38 DEF_PREDICTOR (PRED_COMBINED, "combined", PROB_ALWAYS, 0) | |
| 39 | |
| 40 /* An outcome estimated by Dempster-Shaffer theory. */ | |
| 41 DEF_PREDICTOR (PRED_DS_THEORY, "DS theory", PROB_ALWAYS, 0) | |
| 42 | |
| 43 /* A combined heuristics using probability determined by first | |
| 44 matching heuristics from this list. */ | |
| 45 DEF_PREDICTOR (PRED_FIRST_MATCH, "first match", PROB_ALWAYS, 0) | |
| 46 | |
| 47 /* Heuristic applying when no heuristic below applies. */ | |
| 48 DEF_PREDICTOR (PRED_NO_PREDICTION, "no prediction", PROB_ALWAYS, 0) | |
| 49 | |
| 50 /* Mark unconditional jump as taken. */ | |
| 51 DEF_PREDICTOR (PRED_UNCONDITIONAL, "unconditional jump", PROB_ALWAYS, | |
| 52 PRED_FLAG_FIRST_MATCH) | |
| 53 | |
| 131 | 54 /* Return value of malloc function is almost always non-null. */ |
| 55 DEF_PREDICTOR (PRED_MALLOC_NONNULL, "malloc returned non-NULL", \ | |
| 56 PROB_VERY_LIKELY, PRED_FLAG_FIRST_MATCH) | |
| 57 | |
| 0 | 58 /* Use number of loop iterations determined by # of iterations |
| 59 analysis to set probability. We don't want to use Dempster-Shaffer | |
| 60 theory here, as the predictions is exact. */ | |
| 131 | 61 DEF_PREDICTOR (PRED_LOOP_ITERATIONS, "loop iterations", PROB_UNINITIALIZED, |
| 0 | 62 PRED_FLAG_FIRST_MATCH) |
| 63 | |
| 111 | 64 /* Assume that any given atomic operation has low contention, |
| 65 and thus the compare-and-swap operation succeeds. */ | |
| 66 DEF_PREDICTOR (PRED_COMPARE_AND_SWAP, "compare and swap", PROB_VERY_LIKELY, | |
| 67 PRED_FLAG_FIRST_MATCH) | |
| 68 | |
| 69 /* Hints dropped by user via __builtin_expect feature. Note: the | |
| 70 probability of PROB_VERY_LIKELY is now overwritten by param | |
| 71 builtin_expect_probability with a default value of HITRATE(90). | |
| 72 Refer to param.def for details. */ | |
| 0 | 73 DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY, |
| 74 PRED_FLAG_FIRST_MATCH) | |
| 75 | |
| 131 | 76 /* Hints provided by user via __builtin_expect_with_probability. */ |
| 77 DEF_PREDICTOR (PRED_BUILTIN_EXPECT_WITH_PROBABILITY, | |
| 78 "__builtin_expect_with_probability", PROB_UNINITIALIZED, | |
| 79 PRED_FLAG_FIRST_MATCH) | |
| 80 | |
| 145 | 81 /* Branches to hot labels are likely. */ |
| 82 DEF_PREDICTOR (PRED_HOT_LABEL, "hot label", HITRATE (90), | |
| 83 PRED_FLAG_FIRST_MATCH) | |
| 84 | |
| 85 /* Branches to cold labels are extremely unlikely. */ | |
| 86 DEF_PREDICTOR (PRED_COLD_LABEL, "cold label", HITRATE (90), | |
| 87 PRED_FLAG_FIRST_MATCH) | |
| 88 | |
| 0 | 89 /* Use number of loop iterations guessed by the contents of the loop. */ |
| 90 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_GUESSED, "guessed loop iterations", | |
| 131 | 91 PROB_UNINITIALIZED, PRED_FLAG_FIRST_MATCH) |
| 0 | 92 |
| 111 | 93 /* Use number of loop iterations guessed by the contents of the loop. */ |
| 94 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_MAX, "guessed loop iterations", | |
| 131 | 95 PROB_UNINITIALIZED, PRED_FLAG_FIRST_MATCH) |
| 111 | 96 |
| 0 | 97 /* Branch containing goto is probably not taken. */ |
| 111 | 98 DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (67), 0) |
| 0 | 99 |
| 100 /* Branch to basic block containing call marked by noreturn attribute. */ | |
| 101 DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY, | |
| 102 PRED_FLAG_FIRST_MATCH) | |
| 103 | |
| 104 /* Branch to basic block containing call marked by cold function attribute. */ | |
| 105 DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY, | |
| 106 PRED_FLAG_FIRST_MATCH) | |
| 107 | |
| 111 | 108 /* Edge causing loop to terminate is probably not taken. */ |
| 131 | 109 DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (89), |
| 0 | 110 PRED_FLAG_FIRST_MATCH) |
| 111 | |
| 111 | 112 /* Same as LOOP_EXIT but for loops containing recursive call. */ |
| 113 DEF_PREDICTOR (PRED_LOOP_EXIT_WITH_RECURSION, "loop exit with recursion", | |
| 131 | 114 HITRATE (78), PRED_FLAG_FIRST_MATCH) |
| 111 | 115 |
| 116 /* Edge causing loop to terminate by computing value used by later | |
| 117 conditional. */ | |
| 131 | 118 DEF_PREDICTOR (PRED_LOOP_EXTRA_EXIT, "extra loop exit", HITRATE (67), |
| 0 | 119 PRED_FLAG_FIRST_MATCH) |
| 120 | |
| 121 /* Pointers are usually not NULL. */ | |
| 111 | 122 DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (70), 0) |
| 123 DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (70), 0) | |
| 0 | 124 |
| 125 /* NE is probable, EQ not etc... */ | |
| 131 | 126 DEF_PREDICTOR (PRED_OPCODE_POSITIVE, "opcode values positive", HITRATE (59), 0) |
| 111 | 127 DEF_PREDICTOR (PRED_OPCODE_NONEQUAL, "opcode values nonequal", HITRATE (66), 0) |
| 0 | 128 DEF_PREDICTOR (PRED_FPOPCODE, "fp_opcode", HITRATE (90), 0) |
| 111 | 129 DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", |
| 131 | 130 HITRATE (59), 0) |
| 111 | 131 DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", |
| 132 HITRATE (66), 0) | |
| 0 | 133 DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0) |
| 134 | |
| 135 /* Branch guarding call is probably taken. */ | |
| 111 | 136 DEF_PREDICTOR (PRED_CALL, "call", HITRATE (67), 0) |
| 137 | |
| 131 | 138 /* Call predictors are for now ignored, lets leave the predictor |
| 139 to measure its benefit. */ | |
| 140 DEF_PREDICTOR (PRED_INDIR_CALL, "indirect call", PROB_EVEN, 0) | |
| 141 DEF_PREDICTOR (PRED_POLYMORPHIC_CALL, "polymorphic call", PROB_EVEN, 0) | |
| 142 DEF_PREDICTOR (PRED_RECURSIVE_CALL, "recursive call", PROB_EVEN, 0) | |
| 0 | 143 |
| 144 /* Branch causing function to terminate is probably not taken. */ | |
| 111 | 145 DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (66), |
| 146 0) | |
| 0 | 147 |
| 148 /* Branch containing goto is probably not taken. */ | |
| 111 | 149 DEF_PREDICTOR (PRED_GOTO, "goto", HITRATE (66), 0) |
| 0 | 150 |
| 151 /* Branch ending with return constant is probably not taken. */ | |
| 131 | 152 DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (65), 0) |
| 0 | 153 |
| 154 /* Branch ending with return negative constant is probably not taken. */ | |
| 111 | 155 DEF_PREDICTOR (PRED_NEGATIVE_RETURN, "negative return", HITRATE (98), 0) |
| 0 | 156 |
| 157 /* Branch ending with return; is probably not taken */ | |
| 131 | 158 DEF_PREDICTOR (PRED_NULL_RETURN, "null return", HITRATE (71), 0) |
| 111 | 159 |
| 160 /* Branches to compare induction variable to a loop bound is | |
| 161 extremely likely. */ | |
| 162 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE_GUESS, "guess loop iv compare", | |
| 131 | 163 HITRATE (64), 0) |
| 111 | 164 |
| 165 /* Use number of loop iterations determined by # of iterations analysis | |
| 166 to set probability of branches that compares IV to loop bound variable. */ | |
| 131 | 167 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE, "loop iv compare", PROB_UNINITIALIZED, |
| 111 | 168 PRED_FLAG_FIRST_MATCH) |
| 169 | |
| 170 /* In the following code | |
| 171 for (loop1) | |
| 172 if (cond) | |
| 173 for (loop2) | |
| 174 body; | |
| 175 guess that cond is unlikely. */ | |
| 131 | 176 DEF_PREDICTOR (PRED_LOOP_GUARD, "loop guard", HITRATE (73), 0) |
| 111 | 177 |
| 178 /* Same but for loops containing recursion. */ | |
| 179 DEF_PREDICTOR (PRED_LOOP_GUARD_WITH_RECURSION, "loop guard with recursion", | |
| 180 HITRATE (85), 0) | |
| 181 | |
| 182 /* The following predictors are used in Fortran. */ | |
| 183 | |
| 184 /* Branch leading to an integer overflow are extremely unlikely. */ | |
| 185 DEF_PREDICTOR (PRED_FORTRAN_OVERFLOW, "Fortran overflow", PROB_ALWAYS, | |
| 186 PRED_FLAG_FIRST_MATCH) | |
| 0 | 187 |
| 111 | 188 /* Branch leading to a failure status are unlikely. This can occur for out |
| 189 of memory. This predictor only occurs when the user explicitly asked | |
| 190 for a return status. By default, the code aborts, | |
| 191 which is handled via PRED_NORETURN. */ | |
| 192 DEF_PREDICTOR (PRED_FORTRAN_FAIL_ALLOC, "Fortran fail alloc", | |
| 193 PROB_VERY_LIKELY, 0) | |
| 194 | |
| 195 /* Predictor is used for an allocation of an already allocated memory or | |
| 196 deallocating an already deallocated allocatable. */ | |
| 197 DEF_PREDICTOR (PRED_FORTRAN_REALLOC, "Fortran repeated allocation/deallocation", | |
| 198 PROB_LIKELY, 0) | |
| 199 | |
| 200 /* Branch leading to an I/O failure status are unlikely. This predictor is | |
| 201 used for I/O failures such as for invalid unit numbers. This predictor | |
| 202 only occurs when the user explicitly asked for a return status. By default, | |
| 203 the code aborts, which is handled via PRED_NORETURN. */ | |
| 204 DEF_PREDICTOR (PRED_FORTRAN_FAIL_IO, "Fortran fail IO", HITRATE (85), 0) | |
| 205 | |
| 206 /* Branch leading to a run-time warning message which is printed only once | |
| 207 are unlikely. The print-warning branch itself can be likely or unlikely. */ | |
| 208 DEF_PREDICTOR (PRED_FORTRAN_WARN_ONCE, "Fortran warn once", HITRATE (75), 0) | |
| 209 | |
| 210 /* Branch belonging to a zero-sized array. */ | |
| 211 DEF_PREDICTOR (PRED_FORTRAN_SIZE_ZERO, "Fortran zero-sized array", \ | |
| 212 HITRATE (99), 0) | |
| 213 | |
| 214 /* Branch belonging to an invalid bound index, in a context where it is | |
| 215 standard conform and well defined but rather pointless and, hence, rather | |
| 216 unlikely to occur. */ | |
| 217 DEF_PREDICTOR (PRED_FORTRAN_INVALID_BOUND, "Fortran invalid bound", \ | |
| 218 HITRATE (90), 0) | |
| 219 | |
| 220 /* Branch belonging to the handling of absent optional arguments. This | |
| 221 predictor is used when an optional dummy argument, associated with an | |
| 222 absent argument, is passed on as actual argument to another procedure, | |
| 223 which in turn has an optional argument. */ | |
| 224 DEF_PREDICTOR (PRED_FORTRAN_ABSENT_DUMMY, "Fortran absent dummy", \ | |
| 225 HITRATE (60), 0) | |
| 226 | |
| 227 /* Fortran DO statement generates a pre-header guard: | |
| 228 empty = (step > 0 ? to < from : to > from), which can be predicted | |
| 229 to be very likely. */ | |
| 230 DEF_PREDICTOR (PRED_FORTRAN_LOOP_PREHEADER, "Fortran loop preheader", \ | |
| 231 HITRATE (99), 0) | |
| 145 | 232 |
| 233 /* Fortran assumed size arrays can be non-contiguous, so they need | |
| 234 to be repacked. */ | |
| 235 | |
| 236 DEF_PREDICTOR (PRED_FORTRAN_CONTIGUOUS, "Fortran contiguous", \ | |
| 237 HITRATE (75), 0) | |
| 238 |